To add to a sibling comment, the distinction is important, because observed mass of black holes falls largely into super massive (millions to billions solar mas

To add to a sibling comment, the distinction is important, because observed mass of black holes falls largely into super massive (millions to billions solar masses) to stellar (dozens of solar masses). There is very, very, astonishingly few observed black holes with an intermediate mass. So, how super massive black holes form is a mystery, and finding large stellar mass black holes starts filling in (possibly) that evolutionary gap in black holes. Not a physicist, just read/watch a lot of pop astronomy/cosmology.